Marine riser orientation device

ABSTRACT

A marine riser orientation device enables equipment to be landed on an underwater wellhead without the use of guidelines by providing a sleeve slidably mounted on a tubular orienting member, said sleeve having means to achieve the desired angular position with said tubular member and means to orient the sleeve with respect to the riser. Third means are provided on the tubular orienting member to achieve the desired angular relationship with respect to the underwater wellhead.

United States Patent Albers et al.

[ Sept. 17, 1974 [54] MARINE RISER ORIENTATION DEVICE Inventors: James C. Albers; Gerald E.

Pfenning, both of New Orleans, La.; Adrian P. Anderson, The Hague, Netherlands Assignee: Shell Oil Company, New York, NY.

Filed: Jan. 10, 1973 Appl. No.: 322,596

Foreign Application Priority Data Jan. 10, 1972 Great Britain lll2/72 US. Cl. 166/5, 285/26 Int. Cl. E2lc 19/00 Field of Search 175/5, 7; 166/.5, .6;

References Cited UNITED STATES PATENTS 3/1962 McClintock 166/.6

6/1965 Rhodes et al. 175/7 10/1969 Gibson et al 175/7 X Primary Examiner--Frank L. Abbott Assistant ExaminerRichard E. Favreau Attorney, Agent, or Firm-Harold L. Denkler 57 ABSTRACT A marine riser orientation device enables equipment to be landed on an underwater wellhead without the use of guidelines by providing a sleeve slidably mounted on a tubular orienting member, said sleeve having means to achieve the desired angular position with said tubular member and means to orient the sleeve with respect to the riser. Third means are provided on the tubular orienting member to achieve the desired angular relationship with respect to the underwater wellhead.

11 Claims, 2 Drawing Figures MARINE RISER ORIENTATION DEVICE BACKGROUND OF THE INVENTION The present invention relates to underwater drilling equipment for use in exploration and production of hydrocarbons. The invention is particularly adapted for use as a means for orienting a marine riser, the upper part of a blow-out preventer (BOP) stack or similar equipment correctly on a wellhead for re-entry, or on other equipment disposed on the sea floor. The two parts will be referred to as the riser and wellhead respectively throughout and will refer to the upper and lower portions to be connected irrespective of their function or construction.

SUMMARY OF THE INVENTION In order to re-enter a well under water it is necessary to orient the marine riser in a precise angular position with respect to the wellhead mandrel in order that the hydraulic and/or electrical connections between conduits carried by the riser and corresponding conduits on the wellhead properly mate.

The present invention provides a method and apparatus enabling the riser to be connected to a wellhead in the desired angular orientation without using guide lines or direct control.

A tool for orienting a marine riser in a desired angular position with respect to an underwater wellhead comprises a sleeve slidably mounted on a tubular orienting member arranged to be connected to the lower end of a well re-entry string that is lowered within the riser, the sleeve being provided with a first locating means which mates with the tubular member to orient it in the desired angular position with the member, a second means which orients the sleeve with the riser, and a third means for locating the member in the desired angular position with respect to a wellhead having appropriate cooperating means so that by placing each of the three locating means in their respective positions the riser is properly oriented with respect to the underwater wellhead.

The present invention has the further advantage of positioning the various locating means such that they do not obstruct the internal bore of either the riser, the blow-out preventer or the wellhead mandrel and has achieved this advantage by making the male parts of the locating means situated on the sleeve spring-loaded and retractable.

The present invention extends to a method of orientating a marine riser on a wellhead comprising lowering the riser to a predetermined depth in the region of the wellhead, lowering a tubular orienting member carried by a well re-entry string having an orientation sleeve mounted on it and lowering the orientating member through the inner bore of the riser until the sleeve seats near the foot of the riser, orienting the sleeve with re spect to the member, engaging locating means between the sleeve and the riser by rotation of the member until the locating means engage, lowering the string into the wellhead mandrel and orienting it to a pre-arranged angular position with respect to the latter, lowering the riser, engaging the location means between the sleeve and the tubular member and continuing to lower the riser to make a connection with the mandrel while maintaining its correct orientation by means of the cating means on the sleeve, so that the riser can be connected in the desired angular orientation with respect to the wellhead. The re-entry guidance string, with the sleeve mounted on it, can then be removed. Alternatively, the sleeve can be mounted on the tubular member in the desired angular orientation prior to being lowered in the riser.

BRIEF DESCRIPTION OF THE DRAWINGS DESCRIPTION OF A PREFERRED EMBODIMENT FIG. ll shows a wellhead mandrel 10 which has been engaged by a bumper head 12 at the foot of a well reentry guidance string 14. In the position shown in FIG. 1, the lower end of a marine riser 16 has been lowered to a position such that a female connecting bushing 48 mates with the mandrel l0 and is in locking engagement with it by means of hydraulically operated jaws 46.

In view of the close functional interrelation of the parts of the orientation tool they will be described with reference to their mode of operation.

The marine riser 16 is lowered from a floating vessel (not shown) to a depth which is a prescribed distance above the wellhead. The string 14 is then prepared for lowering inside the riser 16 while the latter is held in a fixed position. The lower member of the string 14 is provided with a sleeve 22 which can slide along the string 14 to a position close to its lower end and latched to it by means of a spring-loaded pawl 54 that engages an annular recess 52 on the string 14.

The string 14 with the sleeve 22 is then lowered through the inner bore 21 of the riser. As it approaches the foot of the riser (i.e., that part shown in the drawing) the sleeve seats on a tapered shoulder 24 provided in the orientation housing 26. Further downward movement of the string moves an inner wedge-shaped bushing 28 downwardly causing bushing 28 to drive a pair of latchdown dogs 30, carried by the sleeve 22, into locking engagement with an annular groove 32 in the housing 26.

Further lowering of the string 14 causes an elongated key 34 in the string 14 to engage a helical entry guide of a keyway 35 in the sleeve 22 and when the key 34 has completely entered the keyway 35 the sleeve 22 is oriented in the desired angular position with respect to the string 14 and is so locked by the key 34 and keyway 35. By rotating the string 14 slowly an outwardly facing, spring-loaded key 36 on the sleeve 22 snaps into a corresponding slot 33 provided in the orientation housing 26 orienting the sleeve with respect to the riser 16.

The string 14 is then lowered to within approximately 10 15 feet above the wellhead. The riser 16 is lifted to expose a jet guidance orifice (not shown) which is approximately 30 feet above the bumper head 12. In this position the sleeve 22 is disengaged from the elongated key 34 so that the string 14 can be freely rotated during the final positioning of the bumper head 12 with respect to the wellhead mandrel 10 using a sonar detector head 38 (as described in our co-pending patent application Ser. No. 204,046, filed Dec. 2, 1971 (P-65 83 After engagement of the undersea equipment, in this case the wellhead mandrel 10, by the bumper head 12 the string 14 is lowered gently until a latch-down dog 42 (whose construction and operation is described in our co-pending application Ser. No. 204,046) in the bumper head 12 engages an annular recess 71 in the inner surface of the mandrel 10. The string 14 is then rotated until a spring-loaded key 44 snaps into a locating slot 45 on the inner surface of the mandrel.

The marine riser 16 is then lowered slowly and the longitudinal key 34 on the string 14 engages the tapered entry to the inner slot 35 in the sleeve 22. When the key 34 has fully entered the said slot, the riser is precisely orientated with respect to the wellhead mandrel 10 and can be lowered into final engagement with the wellhead mandrel 10.

Immediately before engagement of the hydraulic and electrical connections (not shown) on the two parts, the slot 35 in the sleeve 22 disengages the key 34 (by lowering of the riser 16) allowing angular freedom between the two parts so that the connections are not damaged by forceable engagement due to slight misalignment.

The two parts (riser l6 and mandrel 10) are lockably engaged by activating hydraulically powered jaws 46 on the inner bore of the female connecting bushing 48 carried by the lower portion of the riser 16.

The inner cable 58 on which the sonar head 38 is supported is then withdrawn freeing the dogs 42 so that the guidance string 14 can be removed from the riser 16. As the string 14 is lifted the spring pawl 54 on the inner bushing 28 is engaged by the groove 52 lifting the bushing 28 and releasing the dogs 30 from annular groove 32. The upper end of bushing 28 then engages the sleeve 22 lifting it out of engagement with the housing 26.

On removal of the string 14 the entire inner bore of the riser is free and unobstructed.

Referring to FIG. 2 an alternate embodiment is shown in which the sleeve assembly 22 differs from that in FIG. 1 in that the longitudinal key 34' on the string 14' has been replaced with a longitudinal slot 34' which is engageable by a spring-loaded key 35 disposed at the lower end of the sleeve 22'.

As in FIG. 1, the sleeve 22' is mated with the string 14 prior to the latters entry into the riser 16'. A pair of inwardly projecting keys 35 at the base of the sleeve 22' engage a keyway 34' formed in the string and as the sleeve 22 is slid down the string 14, a locking dog 30 snaps into a recess 52 formed in the string therebycompleting the assembly of the sleeve 22' to the string 14.

The riser 16 is then lowered to within approximately 25 feet of the wellhead l and the string 14', together with the sleeve 22, is lowered through the inner bore of the riser. When the sleeve 22' engages a seat 24 formed in the inner bore 21, further downward movement of the string 14' causes the dog 30' to be driven outwardly by the action of the chamfered upper lip 56' of the recess 52 and into the annular recess 32' in the orientation housing 26'.

The string 14 is then rotated slowly until an outwardly facing key 36' on the sleeve 22' snaps into a location slot 33 in the orientation housing 26.

The string is lowered further to feet above the wellhead mandrel 10. The riser is then raised until the jet orifice (not shown) is exposed at which position the keys 35 are clear of the keyway 34 so that the string 14' is free to rotate and be directed to the wellhead 10'.

Final location of the wellhead is achieved by the use of a sonar head 38' which is lowered through the inner bore of the string until it is clear of the bumper head 12. Water is pumped through the jet orifice from the surface vessel to assist in directing the string to the wellhead.

A latch-down dog 42' is engaged with the annular groove in the mandrel 10'. The string is then rotated slowly until a spring-loaded key (not shown, but corresponding to that shown in FIG. 1) snaps into the slot formed in the mandrel.

The marine riser is then lowered to the position at which the keys 35 will engage the keyway 34. The riser is rotated slowly until the keys engage the slot before the riser is lowered onto the mandrel. It may be possible to simplify the re-engagement of these keys in the keyway by marking the string and the riser when they were previously in engagement during the lifting of the riser.

The bushing at the foot of the riser is locked to the mandrel as described with reference to FIG. 1, and the guidance string is removed from the riser by releasing the latch-down dog 42 and lifting the string. The locking key on the bumper head is depressed by a tapered exit. The locking dog 30' is urged back into its slot 52 on the string, thus disengaging the orientation housing and at the same time locking it to the string. The key 36' is urged into its recess in the sleeve by the engagement of its inclined surfaces with an inclined surface at the upper end of its slot. Both keys 35' and 36 are prevented from over-extension which might cause obstruction by retainers 39' and 37' respectively.

The use of either embodiment enables a safe and reliable oriented connection to be made under remote control between any two parts above the wellhead without the use of guide lines while maintaining a full and unobstructed inner bore.

As explained hereinbefore, the riser should be lifted in a certain stage of the operation to expose the jet opening in the guide string. Hydraulic fluid pumped through the jet opening deflects the guide string enabling the operator by controlling the jet force and the orientation thereof (by rotation of the guide string) to bring the lower end of the guide string above the entrance of the wellhead. To prevent undesired noise signals from being picked up by the sonar equipment, the distance between the sonar and the jet opening should be as great as possible. At certain times the riser may be required to be lifted through a distance exceeding the lifting height available in the derrick of 'the rig aboard the vessel from which the operations are carried out. In such a case, use may be made of a telescopic tube coupling normally present in the upper part of the riser. By lifting the riser by means of clamps coupled to the lower element of the telescopic coupling, the lower end of the riser may be lifted over an extradistance equal to the stroke of the telescopic coupling. Separate lifting equipment may be applied for this lifting operation. If the telescopic coupling is equipped with hydraulic cylinders for partially or fully supporting the weight of the riser, these hydraulic cylinders may be used for contacting the coupling during the lifting operation to expose the jet opening.

Although the invention has been described primarily with respect to drilling operations, its use may be equally appropriate between the wellhead or stack and an oil or gas delivery pipe.

We claim as our invention:

1. A device for orienting a marine riser in a desired angular position with respect to an underwater wellhead, said .device comprising:

a marine riser;

a tubular orientating member, said tubular member removably positionable within the inner bore of said marine riser;

a sleeve, slidably mounted on said tubular orientating member;

said sleeve having a first means to mate with said tubular member to orient said sleeve in a desired an gular relationship with said tubular member;

said sleeve having second means to orient said sleeve with said riser; and

said tubular member having means to orient said tubular member in a desired angular relationship with said underwater wellhead, thereby orientating said marine riser with respect to said underwater wellhead.

2. The device of claim 1 wherein the sleeve is provided with a keyway to engage a key carried by said tubular member to obtain the desired angular relationship between said sleeve and said tubular member.

3. The device of claim 1 wherein the sleeve is provided with a spring-loaded key to engage a slot on said riser orienting said sleeve with respect to said riser.

4. The device of claim 1 wherein the tubular member is provided with a spring-loaded key to engage a slot on said wellhead to orient said tubular member with respect to said wellhead.

5. A method of orienting a marine riser with respect to an underwater wellhead, comprising the steps of:

lowering a marine riser to a predetermined depth in the region of the wellhead;

lowering a tubular orientating member carrying an orientation sleeve through the inner bore of said riser;

orienting said sleeve in axial sliding engagement with respect to said tubular member;

engaging locating means between said sleeve and said riser;

aligning said tubular member over said wellhead;

lowering said tubular member into said wellhead;

orienting said tubular member with respect to said wellhead;

lowering said marine riser onto said wellhead while maintaining the desired angular relationship of said riser with respect to said wellhead; and

lockably engaging said marine riser with said wellhead.

6. The method of claim 5 wherein the tubular orientating member and sleeve are lowered through the inner bore of said riser by a well re-entry string extending from the surface of the water.

7. The method of claim 5 wherein said locating means between said sleeve and said riser is engaged by rotating said tubular member.

8. The method of claim 5 wherein the step of orienting said sleeve and said tubular member comprises the steps of:

lowering the tubular orientating member carrying said sleeve through the inner bore of the marine riser until said sleeve seats on a tapered shoulder in said riser; and

further lowering said tubular member until an elongated key on said tubular member engages a keyway provided in said sleeve.

9. The method of claim 5 wherein the tubular member is oriented with respect to said wellhead by rotating said tubular member until key means carried by said tubular member engages a locating slot provided in said wellhead.

10. The method of claim 5 wherein said marine riser and said wellhead are lockably engaged by activating hydraulically powered jaws.

11. The method of claim 5 wherein the top of orienting said sleeve with respect to said tubular member is accomplished prior to the step of lowering said tubular orientating member carrying said orientation sleeve through the inner bore of said riser. 

1. A device for orienting a marine riser in a desired angular position with respect to an underwater wellhead, said device comprising: a marine riser; a tubular orientating member, said tubular member removably positionable within the inner bore of said marine riser; a sleeve, slidably mounted on said tubular orientating member; said sleeve having a first means to mate with said tubular member to orient said sleeve in a desired angular relationship with said tubular member; said sleeve having second means to orient said sleeve with said riser; and said tubular member having means to orient said tubular member in a desired angular relationship with said underwater wellhead, thereby orientating said marine riser with respect to said underwater wellhead.
 2. The device of claim 1 wherein the sleeve is provided with a keyway to engage a key carried by said tubular member to obtain the desired angular relationship between sAid sleeve and said tubular member.
 3. The device of claim 1 wherein the sleeve is provided with a spring-loaded key to engage a slot on said riser orienting said sleeve with respect to said riser.
 4. The device of claim 1 wherein the tubular member is provided with a spring-loaded key to engage a slot on said wellhead to orient said tubular member with respect to said wellhead.
 5. A method of orienting a marine riser with respect to an underwater wellhead, comprising the steps of: lowering a marine riser to a predetermined depth in the region of the wellhead; lowering a tubular orientating member carrying an orientation sleeve through the inner bore of said riser; orienting said sleeve in axial sliding engagement with respect to said tubular member; engaging locating means between said sleeve and said riser; aligning said tubular member over said wellhead; lowering said tubular member into said wellhead; orienting said tubular member with respect to said wellhead; lowering said marine riser onto said wellhead while maintaining the desired angular relationship of said riser with respect to said wellhead; and lockably engaging said marine riser with said wellhead.
 6. The method of claim 5 wherein the tubular orientating member and sleeve are lowered through the inner bore of said riser by a well re-entry string extending from the surface of the water.
 7. The method of claim 5 wherein said locating means between said sleeve and said riser is engaged by rotating said tubular member.
 8. The method of claim 5 wherein the step of orienting said sleeve and said tubular member comprises the steps of: lowering the tubular orientating member carrying said sleeve through the inner bore of the marine riser until said sleeve seats on a tapered shoulder in said riser; and further lowering said tubular member until an elongated key on said tubular member engages a keyway provided in said sleeve.
 9. The method of claim 5 wherein the tubular member is oriented with respect to said wellhead by rotating said tubular member until key means carried by said tubular member engages a locating slot provided in said wellhead.
 10. The method of claim 5 wherein said marine riser and said wellhead are lockably engaged by activating hydraulically powered jaws.
 11. The method of claim 5 wherein the top of orienting said sleeve with respect to said tubular member is accomplished prior to the step of lowering said tubular orientating member carrying said orientation sleeve through the inner bore of said riser. 